Composite structures are commonly used as high-strength, low-weight materials and, therefore, find various applications in the aerospace and automotive industries. A composite structure includes one or more composite layers, wherein each composite layer includes a reinforcement material and a matrix material. The reinforcement material may include fibers. The matrix material may be a polymeric material, such as a thermosetting resin or a thermoplastic resin.
Fiber-reinforced composite structures may be manufactured by laying up multiple layers of fiber tow to form a reinforcement layup. The fiber tow generally includes a bundle of fibers (reinforcement material) impregnated with a matrix material. In fiber placement technologies, the fiber tow is generally supplied in strip/tape form from a bulk reel and is pressed onto the underlying layup at a compaction nip using a compaction roller. The fully assembled reinforcement layup is then cured and/or consolidated, as necessary, to from the composite structure.
When the matrix material of the fiber tow is a thermoplastic resin, the layup process typically requires heating to soften the thermoplastic resin and obtain layer-to-layer consolidation within the reinforcement layup. Typically, a laser beam (e.g., an infrared laser beam) is projected toward the compaction nip to heat the fiber tow and/or the underlying layup during fiber placement. However, laser heating can be difficult to control, resulting in overheating of the fiber tow and/or the underlying layup.
Accordingly, those skilled in the art continue with research and development efforts in the field of laser-assisted fiber placement.